The present invention relates to radiation apparatus in general, and more particularly, to apparatus for producing radiation predominantly in the ultraviolet range of the spectrum. Specifically, the invention relates to apparatus for producing ultraviolet radiation for medical or theraputic applications such as treatment of psoriasis, and/or for cosmetic applications such as quick tanning or portions of the human body.
An apparatus of this general type is known from U.S. Pat. No. 4,095,113, the contents of which is incorporated herein by reference. In that apparatus a series of at least five (and as many as twenty) low-pressure mercury lamps of rod-shaped configuration is arranged in parallel, with each lamp being located in a trough-shaped reflector. The apparatus produces at its outlet a substantially uniform high-density ultraviolet radiation field. A filter intercepts at least the major percentage of the ultraviolet radiation bands below approximately 315 nm (in the so-called UVC range of 200 to 280 nm and UVB range of 280 to 315 nm), so that the field coming in contact with the body of a user consists essentially of the remaining waveband length of ultraviolet radiation, that is, in the UVA range of 315 to 400 nm and at most in a bordering portion of the UVB range.
This apparatus has been found to be highly efficacious for administering treatments to the human body without causing discomfort and burning, e.g., during quick tanning of the skin. A special advantage of this apparatus over any other prior-art apparatus emitting radiation in a wider portion of the ultraviolet range of the spectrum is that a person to be irradiated can assume a position at or in close proximity of the outlet of the apparatus. This is possible because the lamps of the above-mentioned type produce only a minimum amount of heat which is quickly and easily dissipated into the ambient atmosphere, and because the UVB radiation, which could cause a sunburn, is largely absent from the radiation reaching the person being irradiated. As a result of this, relatively large doses of UVA radiation can be applied to selected parts of the body of the user of this apparatus, and relatively short periods of time are required for achieving a pronounced suntan.
However, its use is practical only for the treatment of large parts of the human body, for example the front or the back of a person. In many instances it is merely necessary to treat smaller parts of the body, e.g., the face or an arm, either to effect tanning or for medical purposes (e.g. to treat psoriasis, acne and other skin irregularities or diseases). In the latter instance, the prior-art apparatus is less than fully effective, particularly since the filter largely intercepts radiation within the 300 to 315 nm portion of the UVB range, which is most effective for these purposes. The conventional apparatus is also too large and expensive for such limited applications, since much of the radiation emitted by it will be wasted when only a small body part is to be treated. Also, if the body part to be treated is strongly rounded--as is the case with e.g., the face (including the cheeks and ears) and arms and legs--, the prior art apparatus generally can be successfully used only if the user is resigned to undergoing repeated treatments in each of which the body part is made to assume a different orientation with respect to the emitted radiation field. Furthermore, the apparatus is absolutely useless unless somebody sets aside the required period of time, however short, and utilizes this period for subjecting his or her body to the radiation emitted by this apparatus in its energized condition. In many instances, this conventional apparatus stands idle for days or even weeks, or is being used by only some but not by other prospective users, simply because all or the other of the prospective users do not find, or do not devote, for reasons of inconvenience or preoccupation with other affairs, the time to the use of this apparatus. This, of course, is very disadvantageous, particularly since this apparatus constitutes a substantial investment which is lost if the apparatus is not being used for its intended purpose, and since the appearance (skin color) or general health (because of the beneficial or therapeutic effect of the ultraviolet radiation) of the prospective user are not improved if he or she does not use this apparatus.